Anode Furnace Research Articles

Characterization of a helium discharge for hollow anode furnace atomization non-thermal excitation spectrometry

A discharge in He has been characterized for hollow anode furnace atomization non-thermal excitation spectrometry (HA-FANES). The small surface area of the cathode and high current densities make it possible to stabilize He discharges up to 1200 hPa using a d.c. power supply operating in the constant current mode. Current—voltage characteristics were determined for pressures up to 800 hPa. Characterization at higher pressures was not possible owing to limitations of the power supply. The release of thermionic electrons from the cathode surface at temperatures in excess of 1750 K caused a dramatic decrease in the discharge potential during the atomization cycle. Increased ohmic heating of the cathode with increased currents caused a time shift in the release of thermionic electrons. Excitation temperatures, obtained from Boltzmann plots of five He I lines, decreased slightly as a function of increasing pressure and increased as a function of increasing current. Dramatic decreases in the discharge potential were observed for high concentrations (250 mg ml–1) of NaCl. The potential decreases were too short-lived to permit the accurate measurement of excitation temperatures. Integrated analytical signals increased linearly with increasing pressure.

Hybrid Rotating Arc-Tube Furnace Device for Microsolution Analysis

A hybrid arc-furnace system using a magnetically rotated, concentric-electrode arc connected to a pyrolytic graphite tube furnace is described. The arc is formed between a 5-mm-i.d. graphite tube anode and a W/Th wire cathode. A 0.9-kG magnetic field from a ceramic permanent magnet causes the arc plasma to rotate at about 1.4 kHz, thus forming a diffuse plasma dome covering the end of the anode cylinder. A 10-mm-long ceramic tube connects the furnace to the arc anode. The graphite anode and graphite furnace are housed in the same chamber. Rotation around a horizontal axis allows the system to quickly convert between a sample loading position and a plasma discharge position. Detection limits for various metallic elements are in the ppb and sub-ppb range. Design features and performance data are presented.

Removal of antimony from copper by injection of soda ash

The removal of Sb from molten copper is of importance in the development of processes which can smelt copper concentrates directly into copper in a single furnace. A promising method is injection of oxygen and sodium carbonate in a modified anode furnace. This study encompassed a thermodynamic analysis of the impurity removal reactions and an experimental investigation of antimony removal from molten copper in a 15 kW induction furnace. The results showed that the reaction was controlled by diffusion of Sb in the metal phase. The reaction between metal and injected flux can be divided into two subprocesses-. (1) “transitory contact” reaction to the injected flux particles as they rise through the melt and (2) “permanent contact” reaction across the interface between the metal bath and the supernatant slag layer. On the basis of the experimental work, the overall volumetric mass transfer coefficient (cm3/s) at 1473 K was expressed in terms of the two subprocesses as follows:(k d A) ov = (k d A) pc +(k d A) tc = 1.25Q g 0.29 + 0.28(H Q f ) whereQ g is the injection gas flow rate in normal liters per minute,H is the depth of injection in centimeters, andQ f the rate of flux injection in grams per second.

Contimelt: A New Continuous Melting and Refining Process for Copper

Norddeutsche Affinerie and Métallurgie Hoboken-Overpelt have cooperated together since 1968 in developing a new continuous and energy saving process for the production of copper anodes. The two-stage process comprises a relatively short reverberatory furnace with a shaft mounted eccentrically on its roof, and a drum-type continuous poling furnace which also serves as a holding furnace. Auxiliary equipment includes a skip hoist for charging, waste heat boiler, baghouse, and control room. Raw material, such as blister copper slabs, anode scrap, used anode molds, and copper scrap, is melted continuously and the molten copper drops are refined instantaneously while flowing down the foot of the charge column. Arriving at the hearth, copper and slag separate freely. Slag is skimmed from the bath, and oxidized copper flows through the poling furnace and then, well poled, onto the casting machine. To produce 400 tons of anodes in a conventional reverberatory furnace requires a batch time of at least 24 hours. Contimelt® needs as little as 8 hours, i.e., one shift, for the same output. Compared with conventional reverberatory anode furnaces, Contimelt consumes less than half their primary energy requirements and reduces labor costs by approximately one third.

A Study of Basic Brick from Copper Anode Furnaces

Samples of basic and alumina brick were examined after service in copper anode furnaces. Copper oxides penetrating the brick had reacted with the chrome grains, with the periclase, and with the alumina. These reactions were studied by examining the stability of the compounds formed when copper oxides were heated with various spinels and oxides. In general, spinels of the series CuO R2O3 decomposed to the compound CU2O R2O3 with the liberation of R2O3, when R was Al3+, Cr3+, or Fe3+. With magnesia, cupric oxide formed the mineral güggenit, CuO–MgO, which during heating decomposed with the evolution of oxygen to MgO and Cu2O.

銅のアノード精製とその電解について

銅のアノード精製とその電解について